Donaldson PowerCore air filters are widely known in the heavy-duty market for being reliable, premium products. Their flawless reputation and proven performance make Donaldson filters a perfect match for AMSOIL. In filters featuring PowerCore technology, the media is formed into flutes. These flutes are layered to give a tight, rugged structure to the filter. The fluted channels are alternately sealed allowing air to enter through an open flute and forcing it to exit out an adjacent flute. Dirty air travels in and is filtered in one pass through the media.